Conventional methods for image capture in low-light typically employ one or more corrective measures to properly detect a scene. For example, handheld cameras typically apply high gain to image data captured of a low-light scene. Applying high gain, however, amplifies electronic and photonic noise in additional to amplifying the image signal. As a result, images captured in low-light can appear noisy and contain less high frequency content (e.g., details) due to amplification of the noise. One conventional solution is to introduce additional light to a scene by activating a flash of the camera during capture. This will result in a brighter scene, and can allow for gain to be lowered for capturing image data. However, images captured with flash can produce a harsh flat appearance resulting from the direct lighting. Additionally flash can change the detected color of a scene and cause near objects to appear significantly brighter than far objects. As a result, many artifacts not visible to the naked eye, can appear in image data captured for the scene.
Another approach is to utilize alternative flash arrangements, such as a diffuse flash or indirect flash, to soften the appearance of artificial light. Flash warming filters may be applied to modify the color of the flash's light. However, these solutions are not well suited for compact imaging devices, like portable cameras only having a single flash, wherein the flash is usually embedded in the body and is not adjustable.
Another approach employs digital processing of image data. For example, the digital processing approaches described in Digital Photography with Flash and No-Flash Image Pairs, Petschnigg et al., 2004, and Photography Enhancement via Intrinsic Relighting, Eisemann and Durand, 2004, digitally separate the flash and ambient images to light and detail layers (using adaptive filtering tools like the bilateral filter). These methods, however, take details undiscernibly from the image data resulting in the introduction of additional digital noise to the scene in parts of where the flash image is very dark or (conversely) over-saturated. Accordingly, there exists a desire to correct one or more of the aforementioned drawbacks.